Prince Lazar of Serbia could be canonized by the Orthodox church if he had won at the battle of Kosovo field (not avoided getting conquered by the ottomans, but won a series of battles against them at least). If Vuk Branković had not retreated, the Serbs could have won the battle. They killed one of the 2 princes there (the one that survived became sultan after his father's death). Even the sultan was there, if he and both his sons had died, there would be a succession crisis. The ottomans would have had a harder time getting into Europe, Serbia would be conquered much later, at least after Lazar's death, and he would be seen as a great protector of Orthodox Christianity and Christianity as a whole from heathen invaders.